arch/parisc/math-emu/denormal.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Linux/PA-RISC Project (http://www.parisc-linux.org/)
   4  *
   5  * Floating-point emulation code
   6  *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
   7  */
   8 /*
   9  * BEGIN_DESC
  10  *
  11  *  File:
  12  *      @(#)    pa/fp/denormal.c                $ Revision: $
  13  *
  14  *  Purpose:
  15  *      <<please update with a synopsis of the functionality provided by this file>>
  16  *
  17  *  External Interfaces:
  18  *      <<the following list was autogenerated, please review>>
  19  *      dbl_denormalize(dbl_opndp1,dbl_opndp2,inexactflag,rmode)
  20  *      sgl_denormalize(sgl_opnd,inexactflag,rmode)
  21  *
  22  *  Internal Interfaces:
  23  *      <<please update>>
  24  *
  25  *  Theory:
  26  *      <<please update with a overview of the operation of this file>>
  27  *
  28  * END_DESC
  29 */
  30
  31
  32
  33 #include "float.h"
  34 #include "sgl_float.h"
  35 #include "dbl_float.h"
  36 #include "hppa.h"
  37 #include <linux/kernel.h>
  38 /* #include <machine/sys/mdep_private.h> */
  39
  40 #undef Fpustatus_register
  41 #define Fpustatus_register Fpu_register[0]
  42
  43 void
  44 sgl_denormalize(unsigned int *sgl_opnd, boolean *inexactflag, int rmode)
  45 {
  46         unsigned int opnd;
  47         int sign, exponent;
  48         boolean guardbit = FALSE, stickybit, inexact;
  49
  50         opnd = *sgl_opnd;
  51         stickybit = *inexactflag;
  52         exponent = Sgl_exponent(opnd) - SGL_WRAP;
  53         sign = Sgl_sign(opnd);
  54         Sgl_denormalize(opnd,exponent,guardbit,stickybit,inexact);
  55         if (inexact) {
  56             switch (rmode) {
  57               case ROUNDPLUS:
  58                 if (sign == 0) {
  59                         Sgl_increment(opnd);
  60                 }
  61                 break;
  62               case ROUNDMINUS:
  63                 if (sign != 0) {
  64                         Sgl_increment(opnd);
  65                 }
  66                 break;
  67               case ROUNDNEAREST:
  68                 if (guardbit && (stickybit ||
  69                        Sgl_isone_lowmantissa(opnd))) {
  70                            Sgl_increment(opnd);
  71                 }
  72                 break;
  73             }
  74         }
  75         Sgl_set_sign(opnd,sign);
  76         *sgl_opnd = opnd;
  77         *inexactflag = inexact;
  78         return;
  79 }
  80
  81 void
  82 dbl_denormalize(unsigned int *dbl_opndp1,
  83         unsigned int * dbl_opndp2,
  84         boolean *inexactflag,
  85         int rmode)
  86 {
  87         unsigned int opndp1, opndp2;
  88         int sign, exponent;
  89         boolean guardbit = FALSE, stickybit, inexact;
  90
  91         opndp1 = *dbl_opndp1;
  92         opndp2 = *dbl_opndp2;
  93         stickybit = *inexactflag;
  94         exponent = Dbl_exponent(opndp1) - DBL_WRAP;
  95         sign = Dbl_sign(opndp1);
  96         Dbl_denormalize(opndp1,opndp2,exponent,guardbit,stickybit,inexact);
  97         if (inexact) {
  98             switch (rmode) {
  99               case ROUNDPLUS:
 100                 if (sign == 0) {
 101                         Dbl_increment(opndp1,opndp2);
 102                 }
 103                 break;
 104               case ROUNDMINUS:
 105                 if (sign != 0) {
 106                         Dbl_increment(opndp1,opndp2);
 107                 }
 108                 break;
 109               case ROUNDNEAREST:
 110                 if (guardbit && (stickybit ||
 111                        Dbl_isone_lowmantissap2(opndp2))) {
 112                            Dbl_increment(opndp1,opndp2);
 113                 }
 114                 break;
 115             }
 116         }
 117         Dbl_set_sign(opndp1,sign);
 118         *dbl_opndp1 = opndp1;
 119         *dbl_opndp2 = opndp2;
 120         *inexactflag = inexact;
 121         return;
 122 }